package com.wichell.framework.util;

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

/**
 * Aes加解密
 * 
 * @author kezhan
 *
 */
public class AesUtil {

	private static final String KEY = "AES";

	/**
	 * 加密
	 * 
	 * @param content
	 *            需要加密的内容
	 * @return
	 */
	public static String encrypt(String content) throws Exception {
		KeyGenerator kgen = KeyGenerator.getInstance("AES");
		kgen.init(128, new SecureRandom(KEY.getBytes()));
		SecretKey secretKey = kgen.generateKey();
		byte[] enCodeFormat = secretKey.getEncoded();
		SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
		Cipher cipher = Cipher.getInstance("AES");// 创建密码器
		byte[] byteContent = content.getBytes("utf-8");
		cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
		byte[] by = cipher.doFinal(byteContent);
		return parseByte2HexStr(by); // 加密
	}

	/**
	 * 解密
	 * 
	 * @param content
	 *            待解密内容
	 * @return
	 * @throws NoSuchAlgorithmException
	 * @throws NoSuchPaddingException
	 * @throws InvalidKeyException
	 * @throws BadPaddingException
	 * @throws IllegalBlockSizeException
	 */
	public static String decrypt(String content) throws Exception {
		KeyGenerator kgen = KeyGenerator.getInstance("AES");
		kgen.init(128, new SecureRandom(KEY.getBytes()));
		SecretKey secretKey = kgen.generateKey();
		byte[] enCodeFormat = secretKey.getEncoded();
		SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
		Cipher cipher = Cipher.getInstance("AES");// 创建密码器
		cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
		byte[] result = cipher.doFinal(parseHexStr2Byte(content));
		return new String(result); // 加密

	}

	/**
	 * 将二进制转换成16进制
	 * 
	 * @param buf
	 * @return
	 */
	public static String parseByte2HexStr(byte buf[]) {
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < buf.length; i++) {
			String hex = Integer.toHexString(buf[i] & 0xFF);
			if (hex.length() == 1) {
				hex = '0' + hex;
			}
			sb.append(hex.toUpperCase());
		}
		return sb.toString();
	}

	/**
	 * 将16进制转换为二进制
	 * 
	 * @param hexStr
	 * @return
	 */
	public static byte[] parseHexStr2Byte(String hexStr) {
		if (hexStr.length() < 1) {
			return null;
		}
		byte[] result = new byte[hexStr.length() / 2];
		for (int i = 0; i < hexStr.length() / 2; i++) {
			int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
			int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2), 16);
			result[i] = (byte) (high * 16 + low);
		}
		return result;
	}
}
